Compresser for pumping fluid having check valves aligned with fluid ports

ABSTRACT

A compressor comprises a first cylinder for compressing a fluid and a second cylinder for driving a piston in the first cylinder. The first cylinder comprises a chamber with first and second ends. The piston is reciprocally movable along an axial direction of the chamber for compressing a fluid. Three or more first ports at the first end include at least one first inlet port and at least one first outlet port. Three or more second ports at the second end include at least one second inlet port and at least one second outlet port. Each port has an axial direction parallel to the axial direction of the chamber. A check valve is connected inline with each port along the axial direction of the port.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. Pat. Application Serial No.17/483,452 filed on Sep. 23, 2021. The contents of the aforementionedapplication are incorporated by reference herein.

FIELD

The present disclosure relates generally to fluid compression or pumpingdevices and systems, and specifically to fluid compressors having fluidports and check valves connected to the ports.

BACKGROUND

Fluid compressors are useful for pumping fluids. A fluid compressortypically has a fluid chamber and a pair of fluid ports serving as aninlet or outlet of the fluid chamber. Check valves may be connected tothe fluid ports for controlling fluid flow through the inlet or outletports.

For example, United States patent publication no. US20210270257,published on Sep. 02, 2021, disclosed fluid compressors for pumpingmultiphase fluids. A representative view of a compressor 100 disclosedtherein is shown in FIG. 1 . Compressor 100 includes a compressioncylinder 102 having opposite ends 112 a, 112 b. The compression cylinder100 has a double-acting compression piston for compressing a fluidtowards one or the other of the two ends 112 a, 112 b. The compressionpiston is driven by two hydraulic cylinders each coupled to thecompression cylinder at one of the ends 112 a, 112 b through a centralport. Each end 112 a, 112 b also has two fluid ports 104 a, 104 b spacedfrom the central port, one of which is an inlet port and the other ofwhich is an outlet port. The fluid to be pumped can flow in and out ofcompression cylinder 102 through ports 104 a and ports 104 b. Each port104 a,104 b is connected to a check valve 108 a, 108 b by an elbowconnector 106 a, 106 b. The elbow connectors 106 a,106 b are used andhave sufficient size so that the check valves 108 a, 108 b are offsetfrom the hydraulic cylinders at each end 112 a, 112 b of the compressioncylinder 100. The check valves 108 a,108 b are connected by flanges andpipes to the fluid input source and the output destination. The checkvalves 108 a, 108 b are configured and oriented to control the fluidflow at the ports 104 a, 104 b.

It is desirable to improve the efficiency or performance of such fluidcompressors.

SUMMARY

In an embodiment, the present disclosure relates to a compressor thatcomprises a first cylinder for compressing a fluid. The first cylindercomprises a chamber configured to receive a fluid and having a first endand a second end, a piston reciprocally movable in the chamber foralternately compressing the fluid towards the first or second end, threeor more first ports at the first end of the chamber, the first portscomprising at least one first inlet port and at least one first outletport, and three or more second ports at the second end of the chamber,the second ports comprising at least one second inlet port and at leastone second outlet port. Each one of the first and second ports defines afluid flow path extending along an axial direction of the port. Thecompressor also comprises at least one second cylinder each connectedand configured to drive movement of the piston in the first cylinderthrough one of the first and second ends and a plurality of checkvalves, each associated with one of the first and second ports andconnected inline with the associated port along the axial direction ofthe associated port. The piston is reciprocally movable in the chamberalong an axial direction of the chamber, and the axial directions of thefirst and second ports are parallel to the axial direction of thechamber.

In some embodiments the check valves connected to the inlet ports areoriented to allow the fluid to flow into the compression chamber throughthe inlet ports and the check valves connected to the outlet ports areoriented to allow fluid to flow out of the compression chamber throughthe outlet ports.

In some embodiments, the first ports comprise at least two inlet ports,and the second ports comprise at least two inlet ports. In someembodiments, the first ports comprise at least two outlet ports, and thesecond ports comprise at least two outlet ports.

In at least some of the embodiments presented herein, the compressorfurther comprises a plurality of first conduits each connecting one ofthe check valves to its associated port. In some embodiments, each oneof the first conduits defines a straight fluid path between the checkvalve and the port connected by the respective first conduit.

In some embodiments, the check valves connected to the inlet ports arefirst check valves and the check valves connected to the outlet portsare second check valves and the compressor further comprises a secondconduit connected to the first check valves for connecting a fluidsource to the inlet ports to supply the fluid from the fluid source tothe compression chamber though the inlet ports, and a third conduitconnected to the second check valves for receiving compressed fluid fromthe compression chamber through the outlet ports.

In some embodiments, each of the second and third conduits comprises afirst end comprising a first flange, a plurality of second ends eachcomprising a second flange for connecting the respective second end toone of the check valves and at least one third end comprising a thirdflange and a removable blanking plate coupled to the third flange.

In some embodiments, the first ports comprise two first inlet ports andtwo first outlet ports, and the second ports comprise two second inletports and two second outlet ports.

In some embodiments, the at least one first inlet port is positionedabove the at least one first outlet port, and the at least one secondinlet port is positioned above the at least one second outlet port.

In some embodiments, the check valves are in-line check valves.

In another embodiment, the present disclosure relates to a compressorthat comprises a first cylinder for compressing a fluid. The firstcylinder comprises a chamber configured to receive a fluid and having afirst end and a second end, a piston reciprocally movable in the chamberalong an axial direction of the chamber for alternately compressing thefluid towards the first or second end, a plurality of first inlet portsand a plurality of first outlet ports at the first end of the chamberand a plurality of second inlet ports and a plurality of second outletports at the second end of the chamber. Each one of the inlet and outletports defines a fluid flow path extending along an axial direction ofthe port, the axial directions of the inlet and outlet ports beingperpendicular to the axial direction of the chamber. The compressor alsocomprises at least one second cylinder each connected and configured todrive movement of the piston in the first cylinder through one of thefirst and second ends and a plurality of check valves, each associatedwith one of the inlet and outlet ports and connected inline with theassociated port along the axial direction of the associated port.

In some embodiments, the first inlet ports are positioned above thefirst outlet ports at the first end of the chamber and the second inletports are positioned above the second outlet ports at the second end ofthe chamber.

In some embodiments, the plurality of check valves are in-line checkvalves.

In some embodiments, the compressor further comprises a plurality offirst conduits each connecting one of the check valves to its associatedport. In some embodiments, each one of the first conduits defines astraight fluid path between the check valve and the port connected bythe respective first conduit.

In another embodiment, the present disclosure relates to a system forcompressing a fluid, comprising first and second compressors each asdefined herein. The first and second compressors are connected such thatthe compressed fluid from the outlet ports of the first compressor isfed into the inlet ports of the second compressor for furthercompression.

BRIEF DESCRIPTION OF THE DRAWINGS

In the figures, which illustrate example embodiments:

FIG. 1 is a front perspective view of a comparison compressor;

FIG. 2A is a schematic cross-sectional view of a simplified compressor,according to an example embodiment;

FIG. 2B is a schematic view of the compressor of FIG. 2A in operation ata first state;

FIG. 2C is a schematic view of the compressor of FIG. 2A in operation ata second state;

FIG. 2D is a schematic view of the compressor of FIG. 2A in operation ata third state;

FIG. 2E is a schematic view of the compressor of FIG. 2A in operation ata fourth state;

FIG. 3A is a line graph illustrating schematically the changes in thefluid volume and pressure between an end of the compression chamber andthe piston during a piston stroke in the compressor of FIG. 2A;

FIG. 3B is a line graph illustrating schematically the changes in thefluid volume and pressure between another end of the compression chamberand the piston during a piston stroke in the compressor of FIG. 2A;

FIG. 4 is a schematic cross-sectional view of a simplified compressor,according to another example embodiment;

FIG. 5A is a cross-sectional rear perspective view of a compressoraccording to a further example embodiment;

FIGS. 5B and 5C are partially transparent, front perspective views ofthe compressor of FIG. 5A;

FIG. 5D is a partially transparent, rear perspective view of thecompressor ofFIG. 5A;

FIGS. 5E and 5F are front perspective and top plan views of thecompressor of FIG. 5A;

FIG. 5G is a partially transparent front view of the compressor of FIG.5A;

FIG. 5H is a cross sectional end view of the compressor of FIG. 5A,along the line A-A in FIG. 5G;

FIG. 5I is an end view of the compressor of FIG. 5A;

FIG. 5J is a cross-sectional rear perspective view of the compressor ofFIG. 5A, with some check valves in an open configuration;

FIG. 5K is a cross-sectional rear perspective view of the compressor ofFIG. 5A, with some check valves in an open configuration;

FIG. 6A is a partially transparent, cross-sectional rear perspectiveview of a compressor according to a further embodiment;

FIGS. 6B and 6C are front perspective views of the compressor of FIG.6A;

FIGS. 6D and 6E are top plan and front views of the compressor of FIG.6A;

FIG. 6F is a cross sectional end view of the compressor of FIG. 6A,along the line A-A in FIG. 6E;

FIG. 6G is an end view of the compressor of FIG. 6A;

FIG. 7A is a partially transparent, cross-sectional top perspective viewof a compressor according to a further embodiment;

FIGS. 7B and 7C are front perspective views of the compressor of FIG.7A;

FIGS. 7D and 7E are top plan and front views of the compressor of FIG.7A;

FIG. 7F is a cross sectional end view of the compressor of FIG. 7A,along the line B-B in FIG. 7E;

FIG. 7G is an end view of the compressor of FIG. 7A; and

FIG. 8 is a schematic view of an oil and gas producing well system.

DETAILED DESCRIPTION

It has been recognized that when the compression piston within thecompression chamber of the compressor 100 as shown in FIG. 1 reaches anend of stroke position, a relatively large dead volume (or minimalchamber volume) still undesirably remains within the space between thepiston face and the check valves 108 a or 108 b, particularly in theports 104 a or 104 b and the elbow connectors 106 a or 106 b. This largedead volume leads to decreased pumping efficiency and performance. Thisproblem would be exaggerated when the sizes of the elbow connectors 106a, 106 b and the check valves 108 a, 108 b are increased to provideincreased throughput or to pump certain liquids such as liquids producedfrom a well in oil and gas applications. It is thus desirable to providea fluid compressor with reduced dead volume to increase the compressionratio of the compressor without reducing or limiting the pumpingthroughput.

The present inventor has discovered a number of solutions to address theabove problem. First, connecting a check valve to an inlet/outlet portwithout an elbow connector therebetween can provide a straight,shortened fluid flow path between the port and the check valve, thusreducing the dead volume. The straight flow path will also improve theflow characteristics in the flow path, thereby increasing pumpingefficiency.

As can be appreciated, when the elbow connector between the check valveand the port is eliminated or replaced with a straight connector, thecheck valve can be positioned closer to the port, reducing the pathvolume between the end of the piston and the check valve. This willbeneficially reduce the dead volume (i.e., the volume of compressedfluid retained within the compressor at the end of each stroke) of thecompressor. With a smaller dead volume, the compressor will be able todraw in, compress and expel a larger volume of liquid on each stroke,and provide a higher compression ratio on each stroke.

Due to the limited room at each end of the compression cylinder in thepresence of the hydraulic cylinder coupled to the compression cylinder,the sizes of the inlet and outlet ports and the check valves areconstrained, which in turn limits the fluid throughput. However, thepresent inventor realized that three or more fluid communication portsmay be provided at each end of the compressor to increase the fluidthroughput. For example, at least two of the end ports may be inletports, or at least two of the end ports may be outlet ports. In someembodiments, two inlet ports and two outlet ports may be provided ateach end of the compressor. The multiple inlet or outlet ports can besized and arranged so they are offset from the hydraulic cylinder at thesame end.

Accordingly, an example embodiment herein relates to a compressor forreceiving a fluid supply, compressing the fluid and then moving thefluid to another location. The fluid may be a gas, a liquid or amultiphase fluid that comprises 100% gas, 100% liquid, or any proportionof gas/liquid therebetween. The compressor may include a compressionchamber configured to receive a fluid which is compressed towards afirst end or a second end of the compression chamber by a piston that isreciprocally moveable along an axial direction. The first and secondends of the chamber may each include three or more ports for fluidcommunication. At least one first inlet port at the first end of thecompression chamber and at least one second inlet port at the second endof the compression chamber are configured to allow fluid to enter thecompression chamber. The compressor may also include at least one firstoutlet port at the first end of the compression chamber and at least onesecond outlet port at the second end of the compression chamber, bothconfigured to allow fluid to exit the compression chamber. Movement ofthe piston may be driven by at least one second cylinder connected tothe piston within the first cylinder. The compressor may also include aplurality of check valves, each connected to one of the inlet and outletports, inline with the respective port along the axial direction. Theposition and alignment of the check valves relative to their respectiveport reduces dead volume and provides a straight flow path for fluid inand out of the compression chamber.

In an embodiment the check valves are oriented to be aligned with theaxial direction of movement of the piston within the compressionchamber. In a further embodiment, the check valves are perpendicular tothe axial direction of movement of the piston within the compressionchamber.

In an embodiment, the compressor may have two first inlet ports at thefirst end of the compression chamber and two second inlet ports at thesecond end of the compression chamber. The compressor may also includetwo first outlet ports at the first end of the compression chamber andtwo second outlet ports at the second end of the compression chamber.These ports may advantageously increase space at each end of thecompressor for additional components to be accommodated such as forexample, different sizes of hydraulic cylinders to drive movement of thepiston.

In an embodiment, a first compressor may be configured to be connectedto a second compressor. The first compressor may compress a fluid to afirst pressure P1 and the second compressor may further compress thefluid to a second higher pressure P2.

The compressors may be configured to be operable to transfer multiphasemixtures of substances that comprise 100% gas, 100% liquid, or anyproportion of gas/liquid therebetween, wherein during operation, theratio of gas/liquid is changing, either intermittently, periodically, orsubstantially continuously. The compressors can also handle fluids thatmay also carry abrasive solid materials such as sand without damagingimportant components of the compressor system such as the surfaces ofvarious cylinders and pistons.

An example compressor 200 is schematically illustrated in FIG. 2A. Asdepicted, compressor 200 may include first cylinder 202 for compressinga fluid. First cylinder 202 may include tubular wall 226 with first andsecond end plates 228 a, 228 b at either end. The inner surface oftubular wall 226 and the inner surfaces of end plates 228 a, 228 bdefine compression chamber 204, which has first end 205 a and second end205 b. Piston 206 may be reciprocally moveable within compressionchamber 204 in an axial direction towards first end 205 a or second end205 b as indicated by the arrows in FIG. 2A. Piston 206 dividescompression chamber 204 into two adjacent first and second compressionchamber sections 208 a, 208 b. At first end 205 a of compression chamber204 there may be two ports 210 a, 212 a configured to allow fluid toflow into and out of compression chamber section 208 a. As shown in FIG.2A, ports 210 a, 212 a may be cylindrical linear channels extending fromthe outer vertical side to the inner vertical side of plate 228 a. Atsecond end 205 b there may be two ports 210 b, 212 b configured to allowfluid to flow into and out of compression chamber section 208 b. Asshown in FIG. 2A, ports 210 b, 212 b may be cylindrical linear channelsextending from the outer vertical side to the inner vertical side ofplate 228 b. To each of ports 210 a, 210 b, 212 a, 212 b, respectivecheck valves 216 a, 216 b, 218 a, 218 b may be connected. Check valves216 a, 216 b, 218 a, 218 b, may be any suitable check valve, also knownas a non-return valve, reflux valve, foot valve or one way valve, andare configured to move between an open configuration and a closedconfiguration. When in a closed configuration fluid flow is notpermitted in either direction through the check valve. When in an openconfiguration, the check valves allow fluid to flow through in onedirection only from an inlet side to an outlet side of the check valve.The check valve may switch from a closed configuration to an openconfiguration when the pressure is greater on the inlet side of the portthan the outlet side, creating a pressure differential across the checkvalve. Once the pressure differential reaches a pre-determined value,known as the threshold pressure (also known as the cracking pressure),the check valves are configured to open, permitting fluid flow from theinlet side to the outlet side only. The check valves may be operable tobe adjustable such that the threshold pressure that causes the checkvalve to open may be set at a desired value. The check valves areconfigured to switch from the open configuration back to the closedconfiguration, preventing fluid flow therethrough once the pressuredifferential drops to a lower pressure, known as the reseal pressure.

Check valves 216 a, 216 b, 218 a, 218 b may be any suitable type as isknown in the art. For example, the check valves may be ball checkvalves, diaphragm check valves, swing check valves, lift check valves,in-line check valves or reed valves. In a specific embodiment, checkvalves 216 a, 216 b, 218 a, 218 b may be a threaded in-line check valvesuch as a 3" SCV Check Valve made by DFT Inc.

Check valves 216 a, 216 b, 218 a, 218 b may be connected to theirrespective ports 210 a, 210 b, 212 a, 212 b by any suitable method. Forexample, check valves 216 a, 216 b, 218 a, 218 b may have threadedfittings at either end configured to engage with corresponding threadedfittings at the outer end of ports 210 a, 210 b, 212 a, 212 b. In otherembodiments, check valves 216 a, 216 b, 218 a, 218 b may be configuredto be partially inserted into their respective ports 210 a, 210 b, 212a, 212 b and secured by a suitable method such as welding.

The orientation of check valves 216 a, 216 b, 218 a, 218 b relative toports 210 a, 210 b, 212 a, 212 b will determine if each port functionsas an inlet port or an outlet port. As depicted in FIG. 2A, check valves216 a, 216 b may be oriented such that ports 210 a, 210 b operate asinlet ports to supply fluid to compression chamber 204. This is achievedby connecting the outlet side of check valve 216 a to the outer end ofport 210 a such that, when check valve 216 a is in an openconfiguration, fluid is only permitted to flow into chamber section 208a through port 210 a. Fluid is prevented from flowing out of chambersection 208 a through check valve 216 a at all times by the orientationof check valve 216 a.

Similarly, the outlet side of check valve 216 b may be connected to theouter end of port 210 b such that, when check valve 216 b is in an openconfiguration, fluid is only permitted to flow into chamber section 208b through port 210 b. Fluid is prevented from flowing out of chambersection 208 b through check valve 216 b at all times by the orientationof check valve 216 b.

Check valves 218 a, 218 b may be oriented such that ports 212 a, 212 boperate as outlet ports to remove fluid from compression chamber 204.The inlet side of check valve 218 a may be connected to the outer end ofport 212 a such that, when check valve 218 a is in an openconfiguration, fluid is only permitted to flow from chamber section 208a through port 212 a. Fluid is prevented from flowing into chambersection 208 a through check valve 218 a at all times by the orientationof check valve 218 a.

Similarly, the inlet end of check valve 218 b may be connected to theouter end of port 212 b such that, when check valve 218 b is in an openconfiguration, fluid is only permitted to flow from chamber section 208b through port 212 b. Fluid is prevented from flowing into chambersection 208 b through check valve 218 b at all times.

A pair of inlet conduits 220 a, 220 b may be connected to respectivecheck valves 216 a, 216 b to supply fluid from a fluid source and a pairof outlet conduits 222 a, 222 b may be connected to respective checkvalves 218 a, 218 b, to receive compressed fluid from check valves 218a, 218 b. In the embodiment shown in FIG. 2A, check valves 216 a, 216 b,218 a, 218 b may be positioned inline with their respective ports 210 a,210 b, 212 a, 212 b in the axial direction, which are in turn positionedinline with the axial direction of movement of piston 206.

With reference to FIGS. 2B to 2E, piston 206 may reciprocally movebetween first end of stroke position 224 a at first end 205 a ofcompression chamber 204 (shown in FIG. 2B) and second end of strokeposition 224 b at second end 205 b of compression chamber 204 (shown inFIG. 2D). FIGS. 3A and 3B depict the change in volume of compressionchamber sections 208 a, 208 b with the position of piston 206. Withreference to FIG. 3A, when piston 206 is at position 224 a, the volumeof first compression chamber 208 a is at a minimum volume (also referredto as the dead volume) and increases to a maximum volume once piston 206reaches second end of stroke position 224 b. As piston 206 returns tofirst end of stroke position 224 a, the volume of first compressionchamber will decease back to the minimum volume.

Similarly, as shown in FIG. 3B, the volume of second compression chamber208 b will increase from a minimum volume at the second end of strokeposition 224 b to a maximum volume at the first end of stroke position224 a.

As check valves 216 a, 216 b, 218 a, 218 b are positioned inline withtheir respective ports 210 a, 210 b, 212 a, 212 b, they may bepositioned closer to their respective port. This will beneficiallyreduce the path volume between check valves 216 a, 218 a and piston 206when piston 206 is first end of stroke position 224 a and between checkvalves 216 b, 218 b and piston 206 when piston 206 is second end ofstroke position 224 b. As such, the dead volumes in the compressorsshown in FIGS. 3A and 3B are less than that of the comparativecompressor shown in FIG. 1 .

As will be explained below, as piston 206 reciprocates withincompression chamber 204, fluid may alternately enter, and exit each ofthe compression chamber sections 208 a, 208 b. Flow of fluid in and outof each compression chamber section 208 a, 208 b is controlled by thestate of each of the check valves attached to the ports. One completecycle of compressor 200 is illustrated in FIGS. 2B to 2D, with directionof fluid flow at each stage indicated. Piston 206 may start at first endof stroke position 224 a shown in FIG. 2B and move, via the intermediateposition shown in FIG. 2C to second stroke position 224 b shown in FIG.2D. Piston 206 may then reverse direction from second end of strokeposition 224 b and return to first end of stroke position shown in FIG.2B, via the intermediate position shown in FIG. 2E. The change in volumeand representative examples for the variation in pressure of first andsecond compression chambers 208 a, 208 b are shown in FIGS. 3A and 3Brespectively.

Turning first to FIG. 2B, piston 206 is shown at first end of strokeposition 224 a. Check valves 216 a, 216 b, 218 a, 218 b are all closedsuch that fluid cannot flow into or out of first or second compressionchamber sections 208 a, 208 b. Fluid will already be located in firstand second compression chamber sections 208 a, 208 b having previouslybeen drawn in during previous strokes.

As piston 206 moves in direction indicated by the arrow in FIG. 2B, thepressure in first compression chamber section 208 a will drop as thevolume increases (as shown between (i) and (ii) of FIG. 3A), causing apressure differential to develop between the outer and inner sides ofinlet check valve 216 a. Once the differential pressure reaches thethreshold pressure of valve 216 a, valve 216 a will open and fluid willflow from conduit 220 a into first compression chamber section 208 a,via inlet port 210 a as shown in FIG. 2C. Once valve 216 a is open, thepressure within first compression chamber section 208 a will remaingenerally constant until piston 206 reaches the second end of strokeposition 224 b, (as shown between (ii) and (iii) of FIG. 3A). Oncepiston 206 reaches second end of stroke position 224 b (FIG. 2D), valve216 a will close when the pressure differential between the outer andinner sides of valve 216 a drops and reaches the reseal pressure ofvalve 216 a.

At the same time, movement of piston 206 decreases the volume of secondcompression chamber 208 b and increases the pressure within chambersection 208 b as the fluid within chamber section 208 b is compressed(as shown between (vi) to (vii) of FIG. 3B). This will cause a pressuredifferential to develop between the inner and outer side of outlet checkvalve 218 b. Once the pressure differential reaches the thresholdpressure of valve 218 b, valve 218 b will open and will flow out ofsecond compression chamber section 208 b and into conduit 222 b, viaoutlet port 212 b. Once valve 218 b is open, the pressure within secondcompression chamber section 208 b will remain generally constant (asshown between (vii) to (viii) of FIG. 3B) until piston 206 reachessecond end of stroke position 224 b. Once piston 206 reaches second endof stroke position 224 b (FIG. 2D), valve 218 b will close due to thepressure differential between the outer and inner sides of valve 218 bdropping and reaching the reseal pressure of valve 218 b.

Next, compressor 300 is configured for the return drive stroke. Atsecond end of stroke position 224 b shown in FIG. 2D, all check valveswill be closed and with reference to (iii) of FIG. 3A, first compressionchamber 208 a will be at a maximum volume and contain fluid drawn induring the previous stroke. At the same time, with reference to (viii)of FIG. 3B, second compression chamber 208 b will have its minimumvolume and contain a volume of pressurised fluid (i.e. fluid at a higherpressure than the fluid in first compression chamber 208 a).

As piston 206 moves in the direction indicated by the arrow in FIG. 2D,the pressure in second compression chamber section 208 b will drop asthe volume increases (as shown between (viii) and (ix) of FIG. 3B),causing a pressure differential to develop between the outer and innersides of inlet check valve 216 b. Once the differential pressure reachesthe threshold pressure of valve 216 b, valve 216 b will open and fluidwill flow from conduit 220 b into first compression chamber section 208b, via inlet port 210 b (FIG. 2E). Once valve 216 b is open, thepressure within second compression chamber will remain generallyconstant until piston 206 reaches the first end of stroke position 224a, (as shown between (ix) and (x) of FIG. 3B). Once piston 206 reachesfirst end of stroke position 224 a (FIG. 2B), valve 216 b will closewhen the pressure differential between the outer and inner sides ofvalve 216 b drops and reaches the reseal pressure of valve 216 b.

At the same time, movement of piston 206 decreases the volume of firstcompression chamber 208 a and increases the pressure in chamber section208 a as the fluid within is compressed (as shown between (iii) to (iv)of FIG. 3A). This will cause a pressure differential to develop betweenthe inner and outer side of outlet check valve 218 a. Once the pressuredifferential reaches the threshold pressure of valve 218 a, valve 218 awill open and will flow out of first compression chamber section 208 aand into conduit 222 a, via outlet port 212 a. Once valve 218 a is open,the pressure within first compression chamber section 208 a will remaingenerally constant (as shown between (iv) to (v) of FIG. 3A) untilpiston 206 reaches first end of stroke position 224 a. Once piston 206reaches first end of stroke position 224 a (FIG. 2B), valve 218 a willclose due to the pressure differential between the outer and inner sidesof valve 218 a dropping, reaching the reseal pressure of valve 218 a.

The foregoing movement and compression of fluid within compressionchamber 204 will continue as piston 206 continues to move between thefirst and second end of stroke positions 224 a, 224 b.

Turning to FIG. 4 , an example compressor 200' according to anotherembodiment is shown schematically. Compressor 200' may be generallysimilar to compressor 200 as described above but in this embodiment, ateither end of tubular wall 226 are first and second end plates 228 a',228 b'. At first end 205 a there may be two ports 210 a', 212 a'configured to allow fluid to flow into and out of first compressionchamber section 208 a. Ports 210 a', 212 a' may be cylindrical channelswithin plate 228 a' extending from an outer side to an inner side ofsecond end plate 228 a'. Port 210 a' may extend from the upperhorizontal face to the inner vertical face of first end plate 228 a'.Port 212 a' may extend from the lower horizontal face to the innervertical face of first end plate 228 a'.

Similarly, at second end 205 b there may be two ports 210 b', 212 b'configured to allow fluid to flow into and out of second compressionchamber section 208 b. Ports 210 b', 212 b' may be cylindrical channelswithin plate 228 b' extending from an outer side to an inner side ofsecond end plate 228 b'. Port 210 b' may extend from the upperhorizontal face to the inner vertical face of first end plate 228 b'.Port 212 b' may extend from the lower vertical face to the innervertical face of second end plate 228 b'.

Similar to compressor 200, to each of ports 210 a', 210 b', 212 a', 212b' respective check valves 216 a, 216 b, 218 a, 218 b may be connected.As the outer ends of ports 210 a', 212 a' are on the respective upperand lower faces of first end plate 228 a' and the outer ends of ports210 b', 212 b' are on the respective upper and lower faces of second endplate 228 b', check valves 216 a, 216 b, 218 a, 218 b are positionedperpendicular to the axial direction of movement of piston 206.

As shown in FIG. 4 , ports 210 a', 210 b', 212 a', 212 b' extendvertically though the respective end plate, before turning at 90 degreesinwards. In other embodiments, ports 210 a', 210 b', 212 a', 212 b' mayfollow any other suitable path, such as a curved path.

FIGS. 5A to 5I illustrate a compressor 300, which is an exampleembodiment of compressor 200. Compressor 300 may include first cylinder302 for compressing a fluid within compression chamber 304 having firstend 305 a and second end 305 b (FIG. 5A). First cylinder 302 may includecylinder barrel/tubular wall 326 positioned between first and secondcylinder head plates 328 a, 328 b at respective first and second ends305 a, 305 b of compression chamber 304. First cylinder 302 may alsoinclude piston 306, reciprocally moveable within compression chamber 304in an axial direction towards first end 305 a or second end 305 b.Piston 306 may divide compression chamber 302 into two adjacentcompression chamber sections 308 a (FIG. 5C), 308 b (FIG. 5B). Firstcompression chamber section 308 a may be defined by the interior surfaceof tubular wall 326, a surface of piston 306 and the inner face 336 a offirst head plate 328 a (FIG. 5C). Second compression chamber section 308b may be formed on the opposite side of piston 306 to first compressionchamber section 308 a and may be defined by the interior surface oftubular wall 326, a surface of piston 306 and the inner face 336 b ofsecond head plate 328 b (FIG. 5B).

Piston 306 may be reciprocally moveable within first cylinder 302between a first end of stroke position 324 a (FIGS. 5A and 5B) andsecond end of stroke position 324 b (FIG. 5C). The end of strokepositions may be a physical end of stroke positions whereby for aphysical first end of stroke position, the surface of piston 306 willcontact the inner face 336 a of first head plate 328 a. Likewise, for aphysical second end of stroke position, the surface of piston 306 willcontact the inner face 336 b of second head plate 328 b. More desirably,for example to reduce noise and wear on components of compressor 300during operation, the end of stroke positions are pre-defined end ofstroke positions selected such that when piston 306 is almost at thephysical end of stroke position, but not yet in contact with first orsecond head plates 328 a, 328 b. For example, in an embodiment, apre-defined end of stroke position may be 0.5” away from first or secondhead plates 328 a, 328 b.

Compressor 300 may also include first and second, one way acting,hydraulic cylinders 330 a, 330 b (FIG. 5B) positioned at opposite endsof compressor 300. Hydraulic cylinders 330 a, 330 b may each include ahydraulic piston therewithin, each connected to opposite ends of pistonrod 307 and each configured to provide a driving force that acts in anopposite direction to each other, both acting inwardly towards eachother and towards first cylinder 302, thus driving reciprocal movementof piston 306.

First cylinder 302 and hydraulic cylinders 330 a, 330 b may havegenerally circular cross-sections although alternately shaped crosssections are possible in some embodiments.

With reference to FIG. 5C, first head plate 328 a may have a generallysquare or rectangular shape with a pair of upper first inlet ports 310a, a pair of lower first outlet ports 312 a and centrally located pistonrod opening 332 a. First inlet ports 310 a and first outlet ports 312 amay be circular openings that extend through first head plate 328 a fromouter face 334 a to inner face 336 a of first head plate 328 a.Similarly, with reference to FIGS. 5B and 5H, second head plate 328 bmay have a generally square or rectangular shape with a pair of uppersecond inlet ports 310 b, a pair of lower second outlet ports 312 b andcentrally located piston rod opening 332 b. Second inlet ports 310 b andsecond outlet ports 312 b may be circular openings that extend throughfirst head plate 328 b from outer face 334 b to inner face 336 b offirst head plate 328 b.

First inlet ports 310 a are configured to receive fluid at outer firstend 338 a and communicate fluid to inner second end 340 a inside firstchamber section 308 a (FIG. 5A). Similarly, second inlet ports 310 b areconfigured to receive fluid at outer first end 338 b and communicatefluid to an inner, second end 340 b inside second chamber section 308 b(FIG. 5A).

First outlet ports 312 a are configured to receive fluid from firstchamber section 308 a at inner first end 342 a and communicate fluid toouter second end 344 a. Similarly, second outlet ports 312 b areconfigured to receive fluid from second chamber section 308 b at innerfirst end 342 b and communicate fluid to outer second end 344 b.

Connected to each of first ends 338 a, 338 b of inlet ports 310 a, 310 bmay be respective inlet check valves 316 a, 316 b configured to ensurethat fluid may flow into compression chamber 304 from inlet ports 310 a,310 b (i.e., fluid only travels from first ends 338 a, 338 b to secondends 340 a, 340 b). In some embodiments, inlet check valves 316 a, 316 bmay be connected directly to first ends 338 a, 338 b of inlet ports 310a, 310 b. In the embodiment shown in FIG. 5A, short conduits 346 a,sized to be partially received within first ends 338 a of inlet ports310 a, may be disposed between inlet check valve 316 a and first inletports 310 a to facilitate connection of check valves 316 a. Similarly,short conduits 346 b, sized to be partially received within first ends338 b of inlet ports 310 b, may be disposed between inlet check valve316 b and second inlet port 310 b to facilitate connection of checkvalve 316 b.

Similarly, connected to each of the second ends 344 a, 344 b of outletports 312 a, 312 b may be respective outlet check valves 318 a, 318 bconfigured to ensure that fluid may only flow from compression chamber304 into outlet ports 312 a, 312 b, (i.e., fluid only travels in thedirection from first ends 342 a, 342 b to second ends 344 a, 344 b). Insome embodiments, outlet check valves 318 a, 318 b may be connecteddirectly to second ends 344 a, 344 b of outlet ports 312 a, 312 b. Inthe embodiment shown in FIG. 5A, short conduits 348 a, sized to bepartially received within second ends 344 a of outlet ports 312 a, maybe disposed between outlet check valve 318 a and first outlet port 312 ato facilitate connection of check valve 318 a. Similarly, short conduits348 b, sized to be partially received within second ends 344 b of outletports 312 b, may be disposed between outlet check valve 318 b and secondoutlet port 312 b to facilitate connection of check valve 318 b.

Connections between ports 310 a, 310 b, 312 a, 312 b, conduits 346 a,346 b, 348 a, 348 and check valves 316 a, 316 b, 318 a, 318 b may befacilitated by any suitable method, such as welding or by providingcomplementary threaded ends between adjoining components.

In operation, compressor 300 may operate in a similar manner to aspreviously described for compressor 200. Similar to as described abovefor compressor 200, check valves 316 a, 316 b, 318 a, 318 b are operableto move between open and closed configurations depending on the pressuredifferential across each check valve. When in a closed configuration,fluid is not permitted to flow in either direction through the checkvalve. When in an open configuration, fluid is permitted to flow in onedirection only through the check valve. As shown in FIG. 2A, checkvalves 316 a, 316 b, 318 a, 318 b are all in a closed configuration andfluid may not enter or leave compression chamber 304.

With reference to FIG. 5J, inlet check valve 316 a and outlet checkvalve 318 b are shown in the open configuration. This configuration issimilar to as shown in FIG. 2C for compressor 200 and may occur whenpiston 306 is moving from first end of stroke position 324 a to secondend of stroke position 324 b and the pressure differential across checkvalves 316 a, 318 b has reached the threshold pressure of the valves.With inlet check valves 316 a in an open configuration, fluid can flowas indicated through secondary conduits 360 a, inlet check valveconnectors 364 a, inlet check valves 316 a, conduits 346 a and intofirst compression chamber section 308 a through first inlet ports 310 a.With outlet check valves 318 b in an open configuration, fluid can flowas indicated from second compression chamber section 308 b, throughsecond outlet ports 312 b, conduits 348 b, outlet check valves 318 b,and into outlet check valve connectors 378 b.

With reference to FIG. 5K, inlet check valve 316 b and outlet checkvalve 318 a are shown in the open configuration. This configuration issimilar to as shown in FIG. 2E for compressor 200 and may occur whenpiston 306 is moving from second end of stroke position 324 b to firstend of stroke position 324 a and the pressure differential across checkvalves 316 b, 318 a has reached the threshold pressure of the valves.With inlet check valves 316 b in an open configuration, fluid can flowas indicated through secondary conduits 360 b, inlet check valveconnectors 364 b, inlet check valves 316 b, conduits 346 b and intosecond compression chamber section 308 b through first inlet ports 310b. With outlet check valves 318 a in an open configuration, fluid canflow as indicated from first compression chamber section 308 a, throughfirst outlet ports 312 a, conduits 348 a, outlet check valves 318 a, andinto outlet check valve connectors 378 a.

By providing multiple, smaller inlet and outlet ports on each of firstand second head plates 328 a, 328 b (and corresponding smaller checkvalves and connectors) as opposed to single larger ports on each headplate, larger hydraulic cylinders may be used with compressor 300, whichmay be desirable in some applications such as when compressing a fluidwith a high proportion of liquid.

With reference to FIGS. 5B-D in particular, the fluid communicationsystem is shown, which provides fluid to compressor 300 to be compressedwithin compression chamber 304, may include suction intake manifold 350and pressure discharge manifold 352.

On the fluid intake side of compressor 300, suction intake manifold 350may have two manifold outlets 351 a and 351 b and a single manifoldinlet 351 c. A flange associated with outlet 351 a is connected to firstflange 354 a of inlet connector 356 a. Inlet connector 356 a may includeprimary conduit 358 a, which may have the same interior channel diameteras manifold 350, and a pair of smaller, spaced apart secondary conduits360 a extending orthogonally from primary conduit 358 a (FIG. 5B).Flanges 361 a associated with secondary conduits 360 a are eachconnected to flanges 365 a associated with inlet check valve connectors364 a which are in turn configured to connect to input check valves 316a. As such, inlet connector 356 a and inlet check valve connectors 364 amay provide fluid communication from outlet 351 a of suction intakemanifold 350 to inlet check valves 316 a.

Similarly, a flange associated with outlet 351 b is connected to firstflange 354 b of inlet connector 356 b. Inlet connector 356 b may includea primary conduit 358 b, which may have the same interior channeldiameter as manifold 350, and a pair of smaller, spaced apart secondaryconduits 360 b extending orthogonally from primary conduit 358 b (FIGS.5B, 5D). Flanges 361 b associated with secondary conduits 360 b areconnected to flanges 365 b associated with check valve connectors 364 b,configured to connect to input check valves 316 b. As such, inletconnector 356 b and inlet check valve connectors 364 b may provide fluidcommunication from outlet 351 b of suction intake manifold 350 to inletcheck valves 316 b.

With reference to FIG. 5C, on the fluid pressure discharge side ofcompressor 300, pressure discharge manifold 352 may have two manifoldinlets 353 a and 353 b and a single manifold outlet 353 c. A flangeassociated with inlet 353 a is connected to first flange 368 a of outletconnector 370 a. Outlet connector 370 a may include primary conduit 372a, which may have the same interior channel diameter as manifold 352 anda pair of smaller, spaced apart secondary conduits 374 a extendingorthogonally from primary conduit 372 a. Flanges 375 a associated withsecondary conduits 374 a are connected to flanges 379 a associated withoutlet check valve connectors 378 a, which are configured to connect tooutlet check valves 318 a. As such, outlet connector 370 a and outletcheck valve connectors 378 a may provide fluid communication from outletcheck valves 318 a to manifold inlet 353 a of pressure dischargemanifold 352.

Similarly, a flange associated with inlet 353 b is connected to a firstflange 368 b of outlet connector 370 b. Outlet connector 370 a mayinclude a primary conduit 372 b, which may have the same interiorchannel diameter as manifold 352 and a pair of smaller, spaced apartsecondary conduits 374 b extending orthogonally from primary conduit 372b. Flanges 375 b associated with secondary conduits 374 b are connectedto flanges 379 b associated with outlet check valve connectors 378 b,which are configured to connect to outlet check valves 318 b. As such,outlet connector 370 b and outlet check valve connectors 378 b mayprovide fluid communication from outlet check valves 318 b to manifoldinlet 353 b of pressure discharge manifold 352.

Inlet connector 356 a may also include second flange 382 a at theopposite end of conduit 358 a to first flange 354 a and inlet connector356 b may also include second flange 382 b at the opposite end ofconduit 358 b to first flange 354 b (FIG. 5B). Blanking plates 384 a,384 b may be secured to second flanges 382 a, 382 b respectively.

Outlet connector 370 a may also include second flange 386 a at theopposite end of conduit 372 a to first flange 368 a and outlet connector370 b may also include a second flange 386 b at the opposite end ofconduit 372 b to first flange 368 b (FIG. 5C). Blanking plates 388 a,388 b may be secured to second flanges 386 a, 388 b respectively.

Second flanges 382 a, 382 b, 386 a, 386 b, may be operable to facilitateconnections between multiple compressors, a representative example ofwhich will be discussed later.

The manifolds, conduits and connectors described above may be sizeddependent upon the required output/discharge pressures and output flowrates to be produced by compressor 300 and may be sized in order toachieve a desired maximum required flow velocity through compressor 300.In an embodiment the maximum flow velocity is 23 feet per second. Forexample, in some embodiments, suction intake manifold 350, pressuredischarge manifold 352 and primary conduits 358 a, 358 b, 372 a, 372 bmay all have approximately the same interior channel diameter, such asin the range of 4-6 inches or even greater. Secondary conduits 360 a,360 b, 374 a, 374 b, check valve connectors 364 a, 364 b, 378 a, 378 band conduits 346 a, 346 b, 348 a, 346 b may all have approximately thesame interior channel diameter, such as in the range of 2-4 inches oreven greater. Connections between the manifolds, check valves andconduits described above may be secured by any suitable method, such asby welding or by using threaded connections.

As shown in FIGS. 5A to 5I, compressor 300 is configured with inletports 310 a, 310 b at the top and outlet ports 312 a, 312 b at thebottom of cylinder heads 328 a, 328 b. This configuration may bebeneficial, for example when compressor 300 is handling a fluid thatcontains a significant proportion of solids and/or debris which willmigrate to the bottom of compression chamber 304 due to gravity and willbe pumped out of chamber 304 during reciprocal movement of piston 306.This may increase the reliability of compressor 300 as the accumulationof solids and/or debris within compression chamber 304 is reduced.

However, the configuration of inlet and outlet ports may be selectedaccording to the particular application of compressor 300 and may dependon a number of factors such as the desired inlet (suction) pressure,outlet pressure, gas and liquid volume fraction of the fluid and theproportion of solids and other debris in the fluid.

In other embodiments, the upper two ports on each of cylinder heads 328a, 328 b may be outlet ports whilst the lower two ports may be inletports. This configuration may be beneficial, for example, when handlinga fluid with a higher gas volume fraction and when a lower inletpressure is desired.

Compressor 300 may be in hydraulic fluid communication with a hydraulicfluid supply system which may provide an open loop or closed loophydraulic fluid supply circuit. The hydraulic fluid supply system may beconfigured to supply a driving fluid to drive the hydraulic pistons inhydraulic cylinders 330 a, 330 b.

Compressor 300 may also include a controller to control the operation ofcompressor 300, such as by changing the operational mode of thehydraulic fluid supply system. The control system may include a numberof sensors such as proximity sensors in order to detect the position ofcomponents such as piston 306 within first cylinder 302 or pistonswithin hydraulic cylinders 330 a, 330 b in order to determine whenpiston 306 is approaching or has reached either of the end of strokepositions 324 a, 324 b. The controller may use information from thesensors to control the hydraulic fluid system in order to control andadjust the reversal of piston 306 in either direction. Examples ofhydraulic cylinders, hydraulic fluid supply system and a control systemsuitable for use with compressor 300 are disclosed in US 10,544,783, andUS 20210270257, the entire contents of each of which are incorporatedherein by reference.

Turning to FIGS. 6A to 6G, another embodiment of a compressor 400 isshown, which is an example embodiment of the compressor 200' shown inFIG. 4 . First cylinder 302 of compressor 400 may include cylinderbarrel/tubular wall 326 positioned between first and second cylinderhead plates 428 a, 428 b at respective first and second ends 305 a, 305b of compression chamber 304. First head plate 428 a may have agenerally square or rectangular shape with a pair of upper first inletports 410 a, a pair of lower first outlet ports 412 a and a centrallylocated piston rod opening 432 a (not shown). As shown in FIG. 6A, firstinlet ports 410 a may extend within first head plate 428 a in adownwards direction from first ends 438 a in top face 435 a beforeturning at 90 degrees inwards to second ends 440 a in inner face 436 aof first head plate 428 a. First outlet ports 412 a may extend in anoutwards direction from first ends 442 a in inner face 436 a of firsthead plate 428 a before turning at 90 degrees downwards to second ends444 a in bottom face 437 a of first head plate 428 a.

Similarly, second head plate 428 b may have a generally square orrectangular shape with a pair of upper second inlet ports 410 b, a pairof lower second outlet ports 412 b and a centrally located piston rodopening 432 b (FIG. 6F). Second inlet ports 410 b may extend withinsecond head plate 428 b in a downwards direction from first ends 438 bin top face 435 b before turning at 90 degrees inwards to second ends440 b in inner face 436 a of second head plate 428 a. Second outletports 412 a may extend in an outwards direction from first ends 442 b ininner face 436 a of second head plate 428 b before turning at 90 degreesdownwards to second ends 444 b in bottom face 437 b of second head plate428 b.

Connected to each of the first ends 438 a, 438 b of inlet ports 410 a,410 b may be respective inlet check valves 316 a, 316 b configured toensure that fluid may flow into compression chamber 304 from inlet ports410 a, 410 b (i.e., fluid only travels in the direction from first ends438 a, 438 b to second ends 440 a, 440 b of inlet ports 410 a, 410 b).In some embodiments, inlet check valves 316 a, 316 b may be connecteddirectly to first ends 438 a, 438 b of inlet ports 410 a, 410 b. In theembodiment shown in FIG. 6A, short conduits 346 a, sized to be partiallyreceived within first ends 438 a of inlet ports 410 a, may be disposedbetween inlet check valves 316 a and first inlet ports 410 a. Similarly,short conduits 346 b, sized to be partially received within first ends438 b of inlet ports 410 b, may be disposed between inlet check valves316 b and second inlet ports 410 b.

Similarly, connected to each of the second ends 444 a, 444 b of outletports 412 a, 412 b may be respective outlet check valves 318 a, 318 bconfigured to ensure that fluid may flow into outlet ports 412 a, 412 b,from compression chamber 304 (i.e., fluid only travels in the directionfrom first ends 442 a, 442 b to second ends 444 a, 444 b of outlet ports412 a, 412 b). In some embodiments, outlet check valves 318 a, 318 b maybe connected directly to second ends 444 a, 444 b of outlet ports 412 a,412 b. In the embodiment shown in FIG. 6A, short conduits 348 a, sizedto be partially received within second ends 444 a of outlet ports 412 a,may be disposed between outlet check valves 318 a and first outlet ports412 a. Similarly, short conduits 348 b, sized to be partially receivedwithin second ends 444 b of outlet ports 412 b, may be disposed betweenoutlet check valves 318 b and second outlet ports 412 b.

Configuring compressor 400 such that the inlet and outlet ports are onthe upper and lower faces of cylinder heads 428 a, 428 b providesadditional space on the outer faces 434 a, 434 b of cylinder heads 428a, 428 b. This may provide space for accommodating larger diameterhydraulic cylinders on compressor 400 as desired.

In other embodiments of compressor 400, the upper ports on each ofcylinder heads 428 a, 428 b may be outlet ports whilst the lower portsmay be inlet ports.

Referring to FIGS. 6B to 6E, the fluid communication system thatprovides fluid to compressor 400 may be generally similar to the fluidcommunication system of compressor 300, but is sized to connect to thedifferently positioned check valves 316 a, 316 b, 318 a, 318 b oncompressor 400. The fluid communication system may include suctionintake manifold 450 and pressure discharge manifold 452. Suction intakemanifold 450 may have two manifold outlets 451 a and 451 b and a singlemanifold inlet 451 c. A flange associated with outlet 451 a is connectedto a first flange 354 a of inlet connector 356 a, which is in turnconnected to first inlet check valves 316 a through inlet check valveconnectors 364 a. A flange associated with outlet 451 b is connected toa first flange of inlet connector 356 b which is in turn connected tosecond inlet check valves 316 b through check valve connectors 364 b.

On the fluid pressure discharge side of compressor 400, pressuredischarge manifold 452 may have two manifold inlets 453 a and 453 b anda single manifold outlet 453 c. A flange associated with inlet 453 a isconnected to first flange 368 a of outlet connector 370 a which is inturn connected to first outlet check valves 318 a through outlet checkvalve connectors 378 a. A flange associated with inlet 453 b isconnected to a first flange 368 b of outlet connector 370 b which is inturn connected to second outlet check valves 318 a through outlet checkvalve connectors 378 b.

Providing first and second inlet and first and second outlet portsthrough each of first and second head plates 428 a, 428 b as opposed toa larger single inlet and single outlet port in each head plate may bedesirable in order to reduce the thickness of head plates 428 a, 428 b.For example, the pair of first inlet ports 410 a may each have adiameter of around 2 inches. In order to achieve a similar flow velocityof fluid, a single inlet port to replace ports 410 a would be requiredto have a larger diameter, for example about 4 inches. This wouldundesirably significantly increase the thickness of head plate 428 a inorder to accommodate the larger port within, increasing the size, weightand cost (through the extra material required for the thicker cylinderhead) of the compressor.

Turning to FIGS. 7A to 7G, another embodiment of a compressor 500 isshown, which is another example embodiment of compressor 200 shown inFIG. 2A.

In comparison to compressor 300 described above, first head plate 528 a,whilst generally similar to first head plate 328 a, may be configuredwith a pair of first inlet ports 510 a vertically spaced from each otheron a first side of first head plate 528 a. Similar to first inlet ports310 a, first inlet ports 510 a may extend through first head plate 528 aand are configured to receive fluid at an outer, first end 538a andcommunicate fluid to an inner, second end 540 a inside first chambersection 308 a (FIG. 7A). First head plate 528 a may also be configuredwith a pair of first outlet ports 512 a, vertically spaced from eachother on the opposite side of first head plate 528 a to first inletports 510 a. Similar to first outlet ports 312 b, first outlet ports 512b may extend through first head plate 528 a and are configured toreceive fluid at an inner, first end 542 a inside first chamber section308 a and communicate fluid to an outer, second end 544 a.

Second head plate 528 b may be generally similar to first head plate 328b and may be configured with a pair of second inlet ports 510 bvertically spaced from each other on a first side of second head plate528 b. Similar to second inlet ports 310 b, second inlet ports 510 b mayextend through second head plate 528 b and are configured to receivefluid at an outer, first end 538 b and communicate fluid to an inner,second end 540 b inside second chamber section 308 b (FIG. 7A). Secondhead plate 528 b may also be configured with a pair of first outletports 512 b, vertically spaced from each other on the opposite side ofsecond head plate 528 b to first inlet ports 510 a. Similar to secondoutlet ports 312 b, second outlet ports 512 b may extend through secondhead plate 528 b and are configured to receive fluid at an inner, firstend 542 b inside second chamber section 308 b and communicate fluid toan outer, second end 544 b.

First and second inlet ports 510 a, 510 b may be connected to suctionintake manifold 350 in a similar manner to as described above forcompressor 300 through inlet connectors 356 a, 356 b, inlet check valveconnectors 364 a, 364 b and inlet check valves 316 a, 316 b forsupplying fluid to compression chamber 304, with inlet connectors 356 a,356 b and intake manifold 350 oriented to accommodate the differentinlet port configuration of compressor 500.

First and second outlet ports 512 a, 512 b may be connected to pressuredischarge manifold 352 in a similar manner to as described above forcompressor 300 through outlet check valves 318 a, 318 b, outlet checkvalve connectors 378 a, 378 b and outlet connectors 370 a, 370 b forreceiving fluid from compression chamber 304, with outlet connectors 370a, 370 b and pressure discharge manifold 352 oriented to accommodate thedifferent outlet port configuration of compressor 500.

With reference to FIG. 8 an example oil and gas producing well system1100 is illustrated, which utilises a compressor 1106, which may be anycompressors described above. Oil and gas producing well system 1100 isillustrated schematically and may be installed at, and in, a well shaft(also referred to as a well bore) 1108 and may be used for extractingliquid and/or gases (e.g., oil and/or natural gas) from an oil and gasbearing reservoir 1104.

Extraction of liquids including oil as well as other liquids such aswater from reservoir 1104 may be achieved by methods such as the use ofa down-well pump, which operates to bring a volume of oil toward thesurface to a well head 1102. An example of a suitable down-well pump isdisclosed in U.S. Pat. Application Serial No. 16/147,188, filed Sep. 28,2018 (now U.S. Pat. Serial No. 10,544,783, issued Jan. 28, 2020), theentire contents of which is hereby incorporated herein by reference.

Well shaft 1108 may have along its length, one or more generally hollowcylindrical tubular, concentrically positioned, well casings 1120 a,1120 b, 1120 c, including an inner-most production casing 1120 a thatmay extend for substantially the entire length of the well shaft 1108.Intermediate casing 1120 b may extend concentrically outside ofproduction casing 1120 a for a substantial length of the well shaft1108, but not to the same depth as production casing 1120 a. Surfacecasing 1120 c may extend concentrically around both production casing1120 a and intermediate casing 1120 b, but may only extend fromproximate the surface of the ground level, down a relatively shortdistance of the well shaft 1108.

Natural gas may exit well shaft 1108 into piping 1124 whilst liquid mayexit well shaft 1108 through a well head 1102 to an oil flow line 1133.Oil flow line 1133 may carry the liquid to piping 1124, which in turncarries the combined gas and oil to inlet manifold 351 c of compressor1106. Compressor 1106 may operate substantially as described above tocompress gas and liquid supplied by piping 1124. Compressed fluid thathas been compressed by compressor 1106 may exit though outlet manifold353 c and flow via piping 1130 to interconnect to pipeline 1132.

In another embodiment, a plurality of compressors may be connected inseries in order to provide a pressure boost to a fluid. An advantage tothis approach is that less energy is required to compress fluid, such asgas, in multiple stages.

In an example embodiment, a first compressor may be connected to asecond compressor such that fluid flows through the first compressor tothe second compressor. Fluid at a first pressure P1 may have itspressure boosted to a second pressure P2 (that is greater than P1) bythe first compressor. Fluid may then flow to the second compressor,where the pressure of the fluid will be boosted to a third pressure P3(that is greater than P2).

The first and second compressors may be interconnected in a number ofsuitable configurations in order for fluid that has been compressed incompression chamber sections 308 a, 308 b of the first compressor toflow to the second compressor. For example, when the first and secondcompressors are both similar to compressor 300, second flanges 386 a,386 b (with blanking plates 388 a, 388 b removed) on the firstcompressor may be interconnected to manifold inlet 351or second flanges382 a, 382 b of the second compressor.

In one embodiment, the first and second compressors may have differentspecifications. For example, the second compressor may be configured tohandle fluid at a higher pressure and have hydraulic cylinders and apiston with a larger diameter than the first compressor.

For example, in an embodiment, the first compressor may have an inletpressure of 50 psi and an outlet pressure of 250 psi and the secondcompressor may have an inlet pressure of 250 psi and an outlet pressureof 500 psi.

The compressors may also be employed in other oilfield and othernon-oilfield environments to transfer gas and multi-phase fluidsefficiently and quietly.

Whilst the illustrated embodiments depict compressors with two inletports and two outlet ports on each cylinder head, other variations arecontemplated with different numbers of inlet and/or outlet ports on eachcylinder head.

When introducing elements of the present invention or the embodimentsthereof, the articles “a,” “an,” “the,” and “said” are intended to meanthat there are one or more of the elements. The terms “comprising,”“including,” and “having” are intended to be inclusive and mean thatthere may be additional elements other than the listed elements.

Of course, the above described embodiments are intended to beillustrative only and in no way limiting. The described embodiments ofcarrying out the invention are susceptible to many modifications ofform, arrangement of parts, details, and order of operation. Theinvention, therefore, is intended to encompass all such modificationswithin its scope.

What is claimed is:
 1. A compressor comprising: a first cylinder forcompressing a fluid, comprising a chamber configured to receive a fluidand having a first end and a second end, a piston reciprocally movablein the chamber for alternately compressing the fluid towards the firstor second end, three or more first ports at the first end of thechamber, the first ports comprising at least one first inlet port and atleast one first outlet port, and three or more second ports at thesecond end of the chamber, the second ports comprising at least onesecond inlet port and at least one second outlet port, wherein each oneof the first and second ports defines a fluid flow path extending alongan axial direction of the port; at least one second cylinder eachconnected and configured to drive movement of the piston in the firstcylinder through one of the first and second ends; and a plurality ofcheck valves, each associated with one of the first and second ports andconnected inline with the associated port along the axial direction ofthe associated port, wherein the piston is reciprocally movable in thechamber along an axial direction of the chamber, and the axialdirections of the first and second ports are parallel to the axialdirection of the chamber.
 2. The compressor of claim 1, wherein thecheck valves connected to the inlet ports are oriented to allow thefluid to flow into the compression chamber through the inlet ports andthe check valves connected to the outlet ports are oriented to allowfluid to flow out of the compression chamber through the outlet ports.3. The compressor of claim 1, wherein the first ports comprise at leasttwo inlet ports, and the second ports comprise at least two inlet ports.4. The compressor of claim 1, wherein the first ports comprise at leasttwo outlet ports, and the second ports comprise at least two outletports.
 5. The compressor of claim 1, further comprising a plurality offirst conduits each connecting one of the check valves to its associatedport.
 6. The compressor of claim 5, wherein each one of the firstconduits defines a straight fluid path between the check valve and theport connected by the respective first conduit.
 7. The compressor ofclaim 5, wherein the check valves connected to the inlet ports are firstcheck valves and the check valves connected to the outlet ports aresecond check valves, the compressor further comprising: a second conduitconnected to the first check valves for connecting a fluid source to theinlet ports to supply the fluid from the fluid source to the compressionchamber though the inlet ports; a third conduit connected to the secondcheck valves for receiving compressed fluid from the compression chamberthrough the outlet ports.
 8. The compressor of claim 7, wherein each ofthe second and third conduits comprises a first end comprising a firstflange; a plurality of second ends each comprising a second flange forconnecting the respective second end to one of the check valves; and atleast one third end comprising a third flange and a removable blankingplate coupled to the third flange.
 9. The compressor of claim 1, whereinthe first ports comprise two first inlet ports and two first outletports, and the second ports comprise two second inlet ports and twosecond outlet ports.
 10. The compressor of claim 1, wherein the at leastone first inlet port is positioned above the at least one first outletport, and the at least one second inlet port is positioned above the atleast one second outlet port.
 11. The compressor of claim 1, wherein thecheck valves are in-line check valves.
 12. A compressor comprising: afirst cylinder for compressing a fluid, comprising a chamber configuredto receive a fluid and having a first end and a second end, a pistonreciprocally movable in the chamber along an axial direction of thechamber for alternately compressing the fluid towards the first orsecond end, a plurality of first inlet ports and a plurality of firstoutlet ports at the first end of the chamber, and a plurality of secondinlet ports and a plurality of second outlet ports at the second end ofthe chamber, wherein, each one of the inlet and outlet ports defines afluid flow path extending along an axial direction of the port, theaxial directions of the inlet and outlet ports being perpendicular tothe axial direction of the chamber, at least one second cylinder eachconnected and configured to drive movement of the piston in the firstcylinder through one of the first and second ends; and a plurality ofcheck valves, each associated with one of the inlet and outlet ports andconnected inline with the associated port along the axial direction ofthe associated port.
 13. The compressor of claim 12, wherein the firstinlet ports are positioned above the first outlet ports at the first endof the chamber and the second inlet ports are positioned above thesecond outlet ports at the second end of the chamber.
 14. The compressorof claim 12, wherein the plurality of check valves are in-line checkvalves.
 15. The compressor of claim 12, further comprising a pluralityof first conduits each connecting one of the check valves to itsassociated port.
 16. The compressor of claim 15, wherein each one of thefirst conduits defines a straight fluid path between the check valve andthe port connected by the respective first conduit.
 17. A system forcompressing a fluid, comprising first and second compressors each asdefined in claim 1, wherein the first and second compressors areconnected such that the compressed fluid from the outlet ports of thefirst compressor is fed into the inlet ports of the second compressorfor further compression.